Indicator for construction machines

ABSTRACT

A SYSTEM FOR INDICATING WHEN AUTOMATICALLY CONTROLLED CONSTRUCTION MACHINERY, SUCH AS PAVING MACHINERY, IS NOT RETURNED TO ITS DESIRED OPERATING CONDITION FOR A PREDETERMINED PERIOD OF TIME FOLLOWING A DEVIATION FROM THE DESIRED CONDITION, SUCH AS PATH OF TRAVEL OR THICKNESS OF PAVEMENT.

Jan. 5, 1971 TOLES 3,553,670

INDICATOR FOR CONSTRUCTION MACHINES Filed Feb. 15, 1967 2 Sheets-Sheet 1 I I2). /4 q 7 1| H Illll //A\ lllllllll INVENTOR. FRANK R. TOLES ATTORNEYS Jan. 5, 1971 F. R. TOLES 3,553,670

INDICATOR FOR CONSTRUCTION MACHINES Filed Feb. 13, 1967 ZSheets-Sheet 2 INVENTOR.

' FRANK R. TOLES BY 7%, 9w, m 9- W ATTORNEYS United States Patent 3,553,670 INDICATOR FOR CONSTRUCTION MACHINES Frank R. Toles, Highland, Califi, assignor to Gordon H. Ball, Inc., Danville, Calif., a corporation of Nevada Filed Feb. 13, 1967, Ser. No. 615,430 Int. Cl. G08b 21/00 US. 'Cl. 340267 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to an indicator for construction machinery and more particularly to an indicator for warning when a construction machine of the type which operates on a predetermined grade or path is off the grade or path for a predetermined time.

Construction machines for paving roadways, canal linings and the like are well known. Similarly, machines providing a finished or trim grade for road beds, canal slopes and inverts and the like are also known. Recently, such machines have included means for automatically maintaining the level, grade or path of the machines or working portions of the same.

One such means comprises supporting the working portions of the machines from wheels or tracks by adjustable means such as by hydraulic or electromechanical rams. One such ram is provided at each corner of the working portion support and serves to independently and adjustably support each of the corners from the tracks or wheels whereby activation of the associated ram serves to raise and lower the machine to bring it back into grade.

A grade line or wire is placed alongside the path to be traversed by the machine during its operation and defines the predetermined grade. The wire is set to the desired grade by the use of conventional surveying equipment.

A feeler or sensor attached to the support extends outwardly from each corner of the machine and engages the corresponding grade wire or line. If the machine is below grade, a signal is derived which, through suitable controls, causes the corresponding rams to raise the associated corner of the support. If the corner of the machine is above grade, a signal is derived which controls the ram to lower the support. In general, two grade lines are provided, one on each side of the path to be traversed and four feelers are provided, one at each corner of the machine to control the associated ram.

In normal operation, the off grade condition is corrected within a short time. Thus, correction signals which may persist for more than a predetermined short time indicate an abnormal condition of operation. For example, in a concrete paving machine, a control signal may call for lowering of the machine. If the correction is not made within the predetermined interval, the machine may be floating on the concrete. All that is happening in response to the signal is that tracks or wheels are lifted off of the ground and the machine loses traction. Similarly, should a probe or feeler fall off the grade line, it would signal a high grade condition and the machine would attempt to lower. This would result in the laying of thin pavement.

Steering control systems including a guide line, feelers and controls are also known. Here again it is important to give an indication where the machine has not returned to its proper path within a predetermined time.

It is, therefore, an object of the present invention to 3,553,670 Patented Jan. 5, 1971 provide a control means for machinery of the above character including means for providing a signal when the off grade or path condition persists for a predetermined time. The signal may be a visible or audible warning, or may automatically turn oil the machine.

The foregoing and other objects of the invention will become more clearly apparent from the following description taken in conjunction with the accompanying drawing.

Referring to the drawing:

FIG. 1 is a schematic front elevation of a paving machine which incorporates an indicator in accordance with the present invention;

FIG. 2 is a side elevational view of the machine schematically shown in FIG. 1;

FIG. 3 is an enlarged view, partially in section, of the grade line feeler or sensor;

FIG. 4 shows an indicating circuit in accordance with the present invention; and

lfIG. 5 shows four indicating circuits connected in series.

Referring to FIGS. 1 and 2, independently driven, spaced endless tracks 11 serve to support a paving structure 12 which is adapted to lay the pavement 13. The paving structure 12 forms no part of the present invention. As will be apparent from the following description, the structure which is supported by the tracks may include a cutter, a trimming blade, a bucket or other construction equipment. It is further apparent that the tracks 11 may be located at different elevations as, for example, at the invert end berm of a canal wall whereby the canal wall may be trimmed or paved. It is further apparent that rather than endless tracks 11, four or more wheels may be employed to support and move the oper' ating structure or equipment.

In common with all types of equipment described above is the fact that a final grade is established which determines the finished grade of the surface or the thickness of the pavement, or that the path of the machine is controlled. The depth of the cut or thickness of the pavemen-t and direction is accurately determined and maintained. The operating equipment is adjustably supported from the spaced tracks and means: are provided for guiding the equipment.

The supporting means schematically illustrated comprise four hydraulic rams 14, one located at each corner of the structure to support the equipment 12 at a suitable elevation from the tracks 11. Each of the hydraulic rams 14 is independently adjustable whereby any corner can be raised or lowered for adjusting the grade or elevation of the equipment. It is, of course, understood that rather than hydraulic rams, electromechanical rams may be employed.

The elevation of the equipment at each corner is continuously maintained by suitable control means which serve to either control the electric current to the electromechanical rams or the hydraulic fluid to the hydraulic rams 14.

Such control means may include a taut grade Wire 16 suitably supported by spaced posts 17. A wire 16 is supported on each side of the path to be traversed by the machinery and is adapted to be engaged by a sensor or feeler 18 carried by a support means 19 attached to the equipment 12. One such feeler is carried at each corner of the machine.

Many types of feelers are known. A suitable one is shown in FIG. 3 and includes a body 21 supported from support 22. A pair of spaced switches 23 and 24 are mounted on the body with their actuating members adjacent to a feeler arm 26. The feeler is pivoted at pin 27 and includes an open or slot portion 28 adapted to engage and receive the taut grade line 16. Spaced stops 29 limit the pivotal movement of the arm 26. If the equipice ment is below grade, the wire will pivot the arm 26 upwardly and activate the switch 24. If the machine is above grade, it will pivot the arm 26 and serve to actuate the switch 23.

The switch may be incorporated in any suitable electrical circuit which then serves to control either the electric current to the electromechanical rams or valves which control the hydraulic fluid to the hydraulic rams to lower or lift the support to bring the machine back to grade.

Referring to FIG. 4, a circuit incorporating the present invention is schematically illustrated. The circuit associated with a single hydraulic ram 14 and feeler 21 is illustrated, it being understood that the circuit associated with the other rams are identical. Hydraulic fluid is applied to the ram by line 31 connected to a two-way electrically activated hydraulic valve 32. A pump 33 serves to pump the hydraulic fluid into the ram and a reservoir 34 reoeives fluid from the ram. Depending upon the position of the valve 32, fluid is either pumped by the pump into the ram or fluid is released from the ram and returned to the reservoir 34.

The electrical circuit is connected to a voltage supply 36 which may, for example, be a 12 volt battery having one terminal grounded. As illustrated, voltage supply 36 is connected to one terminal of each of the switches 23 .and 24. The other terminal of the switches is connected to the lines 37 and 38, respectively. The lines 37 and 38 are connected to the coils 41 and 42 of relays which include contacts 43 and 44, respectively. The contact 43 is connected in series between the coil 46 of the valve 32 and the supply 36 to energize the coil to move the valve membenfrom a neutral position to a position which would serve to allow fluid to be pumped into the ram 14 to raise the equipment, whereas the contact 44 is connected in series between the coil 47 and the supply to drive the valve in such a position whereby fluid flows from the ram 14 into the reservoir to lower the equipment. Thus, the ram 14 is controlled or actuated responsive to the closing of switches 23 and 24 and in the neutral position. No fluid is withdrawn or inserted into the ram when the valve 32 is in its neutral position.

In accordance with the present invention, if the voltage to either the coil 46 or 47 persists or is present for a predetermined period of time, a warning signal is generated which serves to warn the operator that the adjustment of the associated ram was not made within a predetermined time. The predetermined time selected depends on the particular type of equipment. It can be determined empirically after operation of the equipment for a short period of time. Obviously, in paving equipment, the equipment must go back to grade within a predetermined time, 2 or 3 seconds, or the equipment is floating or the probe fallen '01? the line, or some other malfunction has occurred. In any event, a warning is provided which serves to warn the operator that operation is abnormal.

The warning signal or indication is provided by a time delay means 51. The time delay means may comprise a time delay relay which includes a coil 52 having suitable delay circuits such as capacitive-resistive circuits which, after a predetermined period of time, serve to activate the contact or closure 53. The closure 53 serves to connect the supply voltage to the coil 54 of a relay which has a normally open contact 56 and a normally closed contact 57.

Normally open contact 56 is shown connected in series between the voltage supply, a warning light 58 and a sounding device 59. It is apparent that a single indicating device might be used. There is provided either a visual or audible indication, or both, when the contact is closed.

In addition, a second contact 57 is provided and adapted to be connected in circuit with the corresponding contacts of the control systems for the other three rams. In FIG. 5, the normally closed contacts 57 are shown serially connected and labeled 57a-57c. Upon energization of any one of the coils 54a-54c, one of the contacts will open the contact 62. Opening of the contact 62 may turn off all power on the machine except power to the warning system whereby a warning signal is generated by the light 58 or sounder 59. The operator then must override the switch 62 and bring the machine back into normal operation.

The path followed by the machinery is controlled by a guide wire and feeler means which serves to control the driving means for the spaced tracks. The track drive may be electrical, hydraulic or other with suitable controls responsive to signals from the sensor to control the driving of the tracks and cause the equipment to follow a predetermined path.

It has been found that with an indicator of the above character integrated in construction machinery, considerable savings in time in paving, trimming and other construction operations has resulted. Furthermore, the finished grade in trimming operations, the final thickness of pavement and the direction of the same has been maintained within narrow predetermined limits beca se of the quick response of the machinery and the warning provided an operator whereby a large off grade or path condition cannot result without there being a Warning.

I claim:

1. Construction machinery of the type described including a sensor which cooperates with a grade or guide line and develops a control signal to reestablish the position of the machinery when the sensor engages the line and a time delay means connected to receive said control signal and providing a Warning when said control signal persists for a predetermined period of time greater than the normal correction time whereby to provide a warning if the position is not reestablished within said time.

2. Construction machinery as in claim 1 in which said time delay means comprises a time delay relay.

3. Construction machinery of the type described including a working portion adjustably supported from wheels or tracks by adjustable support means, means including a sensor and a grade line for generating a control signal for controlling said adjustable support means to maintain the working portion at a suitable elevation above the ground and time delay means in said control circuit to receive the control signals and provide a warning signal after the control signal persists for a predetermined period of time greater than the normal correction time whereby to provide a warning if the working parts are not returned to their suitable elevation within a predetermined time.

References Cited UNITED STATES PATENTS 2,043,4l3 6/1936 Knox et al. 340*267X 2,750,583 6/1956 McCullough 340-282X 3,363,231 1/1968 Grosgebaner et al. 34052 2,844,882 7/1958 Earley et al. 37UX THOMAS B. HABECKER, Primary Examiner D. L. TRAFTON, Assistant Examiner U.S. c1. X.R. 

